Hi there! I'm new to this forum. Is there a Pdf to dwg converter that is an open-source or General Public Lisence (GPL)? Any input would be much appreciated.

This should get you by for a while  http://anydwg.com/pdf-to-dxf.htmlFree trial good for 20 uses.Let me know if you find a completely free version, I'm looking for one myself.

The latest version of AutoCAD 2009 can read (attach) PDF files as xrefs and you can osnap to the lines in PDFs.

Happy New Year,
A good free pdf to dwg converter can be found at aidecad.com
The converter will convert the pdf to a dxf file and when you open it you just save the file as a dwg.
Hope that helps.